Language is one of the most amazing things that we are capable
of.
It may even be that we -- Homo sapiens -- are the only creature on the
planet that have it. Only the dolphins show any indication of
language,
although we are as yet unable to understand them.

We seem to be “built” to speak and understand language. The
specialized
areas of the brain, such as Broca’s and Wernicke’s areas, suggest that
genetics provides us with, at very least, the neurological foundations
for language.

Linguistics is, of course, a whole separate subject matter, but it
does
overlap with psychology quite a bit, especially in regards to language
development in infants and children. The ability young children
have
of learning a language -- or even two or three languages simultaneously
-- is one of the indications that there is something special about our
brains at that age.

It all begins in infancy. From birth until around 6 months,
babies
make a great deal of noise. They squeal, squeak, growl, yell, and
give us raspberries. And they coo. Cooing is basically the
production of what will later become vowels (a, e, i, o, and u).

From 6 months to about 10 months, they produce somewhat more
complicated
sounds called babbling. First, they practice their vowels
more precisely, starting with the round, back vowels (oo, oh, ah...)
and
working their way to the unrounded front vowels (ee, eh, ay...).
The first consonants are h, m, and b, which can be combined with the
vowels
to make syllables. Soon, they add p, t, d, n, w, f, v, and
y.
A little while later, they add k, g, and ng.

Then they start adding s and z. It takes a little longer for
babies
to get sh, ch, j, and the infamous th sounds. The very last
sounds
are l and r. This is why you hear them pronouncing works as oddly
as they sometimes do. Fis does fine for fish, soozies for shoes,
Wobbut for Robert, Cawa for Carla, and so on. But keep in mind
that
they can perceive far more than they can pronounce -- something
appropriately
called the fis phenomenon.
They will not be able to say certain
words,
but they won’t put up with you mispronouncing them! One of my
daughters,
for example, used the syllable yã (with a nasal a) to mean shoe,
sock and even chair -- but understood the difference quite well.

Mothers (and fathers) play a huge part in forming the child’s
language.
Even if we are “preprogrammed” in some way to speak language, we need
to
learn a specific language from the people around us. Mothers
typically
adjust their speech to fit the child’s level. This is called motherese.
It is found in practically every culture on the planet, and it has
certain
common characteristics: The “sentences” are very short, there is
a lot of repetition and redundancy, there is a sing-song quality
to it, and it contains many special “baby words.” It also is
embedded
in the context of the immediate surroundings, with constant reference
to
things nearby and activities that are going on here-and-now.

Motherese often involves a subtle shaping called a protoconversation.
Mothers even involve infants who do little more than coo or babble in
protoconversations:

Mother

Child (one year old)

Look! (getting child's attention)

(the child touches the picture)

What are these? (asking a question)

(the child babbles, smiles)

Yes, they are doggies! (naming the object)

(the child vocalizes, smiles, looks at mom)

(mom laughes) Yes, doggies! (repeating)

(the child vocalizes, smiles)

(laughs) Yes! (giving feedback)

(the child laughs)

Moms also ask questions like “where is it?” and “what’s it
doing?”
Any response at all is rewarded with happiness! Of course, the
conversation
becomes more meaningful when the child can actually form his or her own
words. By 10 months, most kids understand between 5 and 10
words.
The fastest 1/4 of them have up to 40 words!

From 12 to 18 months (or thereabouts) is called the one word
(or holophrastic) stage. Each word constitutes a sentence
all by itself. By 12 months, most kids can produce 3 or 4 words,
and understand 30 to 40. Again, there are some kids who
understand
and even use as many as 80! By 14 months, the number of words
understood
jumps to 50 to 100, and even the slowest 1/4 know 20 to 50. By 18
months, most kids can produce 25 to 50 words on their own, and
understand
hundreds.

Two characteristics of this stage are overextension and underextension.
For example, the word hat can mean just about anything that can be put
on your head, a “goggie” applies to just about any animal, and “dada”
(much
to the embarrassment of moms everywhere) pretty much means any man
whatsoever.
On the other hand, sometimes kids engage in underextension, meaning
that
they use a general word to mean one very specific thing. For
example,
“baba” may mean MY bottle and my bottle only, and “soozies” may mean MY
shoes and no one else’s.

There are certain common words that show up in most children’s early
vocabularies. In English, they include mama, daddy, baby, doggy,
kitty, duck, milk, cookie, juice, doll, car, ear, eye, nose, hi,
bye-bye,
no, go, down, and up. There are also unique words, sometimes
actually
invented by the child, called idiolects. Identical twins
sometimes
invent dozens of words between themselves that no one else understands.

Between 18 to 24 months (approximately), we see the beginnings of
two
word sentences, and telegraphic speech. Here are some
common
examples, showing a variety of grammatical functions taken over by
simple
conjunction of the two words:

After 24 months, children begin to use grammatical constructions of
various
sorts. Here are some in their usual order of development:

I walking (-ing
participles used as verbs) in basket, on floor (prepositions)
two balls (the plural)
it broke (verbs in an
irregular past tense)
John’s ball (possessive
‘s)
There it is (the verb to be)
A book, the ball (articles)
John walked (verbs in the
regular past tense)
He walks (third person singular
of verbs)
She has (irregular third
person singular)
It is going (the progressive formation of
verbs)
It’s there (contractions)
I’m walking (complex verbs)

Grammatical gender is not an
easy thing to learn, ether. French
masculine
and feminine words and German masculine, feminine, and neuter words are
just a matter of memorization. The same difficulty applies to
different
classes of verbs.

Aspect (such as
differentiating between things that are done once
and
for all, and things that are done repeatedly -- the perfect and the
imperfect)
is learned before tense
(past-present-future). Tense is actually
quite difficult, even though as adults we take it for granted.

There do seem be languages that are easier for children to learn,
and
others that are more difficult: Some languages (Turkish,
Hungarian,
and Finnish, for example) use many suffixes
to indicate a variety of
grammatical
and semantic qualities. These suffixes are very common, complete
syllables, and fully regular-- and are learned easily and early.

On the other hand, some languages (e.g. Chinese, Indonesian, and to
some extent English) prefer to use small words called particles (e.g.
the,
of, in, and, and so on). These tend to be learned late, because
they
have no meaning of their own and are often unstressed and unclearly
pronounced.
Notice, for example, that "is" and "not" are
often reduced to 's and n't!

A third group -- which contains most European and Semitic languages
-- have a mixed system, including lots of very irregular, unstressed
endings
and particles. If you recall the effort you put into remembering
the German article or Spanish conjugations or Latin declensions of the
nouns, you realize why children have a hard time learning these things
as well.

Language learning doesn’t end with two year olds, of course.
Three
year olds are notorious for something called over-regularization.
Most languages have irregularities, but 3 year olds love rules and will
override some of the irregulars they learned when they were 2, e.g. "I
go-ed" instead of I went and "foots" instead of feet. Three year
olds can speak in four word sentences and may have 1000 words at their
command.

Four year olds are great askers of questions, and start using a lot
of wh- words such as where, what, who, why, when (learned in that
order).
They can handle five word sentences, and may have 1500 word
vocabularies.

Five year olds make six word sentences (with clauses, no less), and
use as many as 2000 words. The first grader uses up to 6.000
words.
And adults may use as many as 25,000 words and recognize up to 50,000
words!

One of the biggest hurdles for children is learning to read and
write.
In some languages, such as Italian or Turkish, it is fairly easy:
Words are written as they are pronounced, and pronounced as they are
written.
Other languages -- Swedish or French, for example -- are not too
difficult,
because there is a lot of consistency. But other languages have
terribly
outdated spelling systems. English is a clear winner among
languages
that use western alphabets. We spend years of education on
getting
kids to memorize irrational spellings. In Italy, on the other
hand,
spelling isn't even recognized as a school subject, and "spelling bees"
would be ridiculous!

And then there are languages that don't use alphabets at all:
Chinese requires years of memorization of long lists of symbols.
The Japanese actually have four systems that all children need to
learn:
A large number of kanji symbols, adopted centuries ago from the
Chinese;
two different syllabaries (syllable-based "alphabets"); and the western
alphabet! The Koreans, on the other hand, have their own alphabet
with a perfect relationship of symbol to sound.